500 Transactions, — Geology. 



rapidly, accompanied by a singing sound ; falls to pieces, and becomes 

 translucent on the tliin edges ; breaks with a conchoidal fracture ; adheres 

 strongly to the tongue ; yields to the thumb nail and affords a shining 

 streak ; possesses an earthy smell. 



Schrotterite ? — Malvern Hills. (Labelled " Finite.") 



In rounded wax-like masses, filling the cavities of an amygdaloidal 



trachyte (?) rock, and as a mammillated incrustation upon its surface ; 



green, grey, and white; hardness about 3-5; streak white, rather tough; 



breaks into more or less conchoidal flakes ; translucent ; waxy lustre. 



Before the blow-pipe it becomes white and opaque, and much harder (thus 



differing from the ordinary behaviour of both pinite and allophane), intu- 



mesces slightly, and tinges the flame green ; affords deep blue when ignited 



with cobalt nitrate ; does not gelatinize with hydrochloric acid, but granular 



silica is thrown down ; gives off much water when heated in closed tubes. 



Zeolites.* 



Xatrolite. — Suunyside, Dunedin . 



In radiated tufts of white acicular crystals, and coating a hemispherical 



concretion of ferruginous calcite. 



Presented by Mr. D. MiUar. 



NatroHte. 



In beautiful radiated tufts of acicular crystals. 



NatroUte. — Dunedin. 



Natrolite. — Dunedin. 



NatroUte. — Dunedin. 

 Associated with an incrustation of siderite or iron carbonate. 



Natrolite. — Dunedin . 

 Compact form, exhibiting radiate structure ; lining amygdaloidal cavi- 

 ties in basalt. 



NatroUte. — Dunedin. 



Forming a thin investing coating on interior of amygdaloidal cavity. 

 Stilbite ? — Dunedin. 



In the cavities of these specimens are minute detached crystals of one 

 of the zeolites. The form appears to be that of the rhombic prism capped 

 with the pyramid; this is a combination often assumed by stilbite, and in 

 addition the little crystals possess a very high lustre, not unlike that of 

 stilbite ; moreover, they behave like that mineral before the blow-pipe, hence 

 they probably belong to the same species. 



Not sufficient to permit an analysis to be made without destroying the 

 specimens completely. 



* Eep. N.Z. Exh., 1865, p. -138. 



